Home Innovation Insights

Water ratings like WRI are voluntary tools that can be used to bolster water efficient home construction.

Cindy Wasser, MBA
September 12, 2022

Why is it Important that WRI is Included within an I-Code?

What is the Water Rating Index (WRI)?

The 2020 National Green Building Standard ICC-700 includes a performance path for residential builders and developers to demonstrate water efficiency. The Water Rating Index (WRI), included as an appendix within the standard, is a methodology by which a 0 to 100 score is assessed for a property’s total indoor and outdoor water use, compared to baseline conditions.

The WRI offers an important new metric that they can use to communicate expected water use to potential buyers. Like HERS and ERI for energy performance, WRI facilitates straightforward comparison across similar properties.

Why is it important that the WRI is included within an I-Code?

Besides WRI, there are a handful of voluntary water ratings available for residential buildings. Water rating programs are young but quickly gaining traction with residential builders, especially in light of rising utility rates and water shortages in some regions.

The inclusion of WRI within an I-code lends credibility to water performance ratings and raises their prominence in the market.

The 2020 NGBS is an ANSI-approved standard, meaning that it was developed through an open consensus development process with input from various stakeholders, including builders, developers, architects, code officials, government representatives, and manufacturers. Industry leaders had the opportunity to provide review and comment on the WRI methodology. This open process helps to ensure that the methodology was developed with reasonable assumptions and sound water usage data.

If we have robust building and plumbing codes, what value does the WRI offer?

Building codes are largely focused on health, safety, and welfare. The residential and commercial building codes address some water concepts, with a focus largely on proper pressurization and leak reduction.

Plumbing codes govern the installation and inspection of plumbing systems to promote the public’s health, safety, and welfare. The plumbing codes are largely focused on the proper installation of specific water-using components. Plumbing codes address the design and performance of water supply and distribution, as well as fixtures and fitting.

The building and plumbing codes were not designed to promote water conservation with a focus on the entire building’s design and construction. The WRI offers a valuable lens that can help builders ensure that they are constructing buildings as efficiently as possible, and, where relevant, in alignment with local water restrictions.

Why should code officials support residential water ratings and certifications?

For local code officials, water ratings like WRI are voluntary tools that they can use to bolster water efficient home construction in their jurisdiction. A jurisdiction could implement an incentive or requirement that new residential buildings achieve a WRI score at or below a certain score.

The simple design of the WRI rating system makes implementation and communication of water conservation measures straightforward. As the WRI is based on a simple 100-point scale, each lower value on the scale conveys 1% water efficiency gain.

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